The present invention relates to an opening device for packages of pourable food products.
Many pourable food products, such as fruit juice, UHT milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
A typical example of such a package is the parallelepiped-shaped package for liquid or pourable food products known as Tetra Brik or Tetra Brik Aseptic (registered trademarks), which is formed by folding and sealing laminated strip packaging material. The packaging material has a multilayer structure comprising a layer of fibrous material, e.g. paper, covered on both sides with layers of thermoplastic material, e.g. polyethylene, and, in the case of aseptic packages for long-storage products, such as UHT milk, also comprises a layer of barrier material defined, for example, by an aluminum film, which is superimposed on a layer of thermoplastic material and is in turn covered with another layer of thermoplastic material eventually defining the inner face of the package contacting the food product.
As is known, such packages are produced on fully automatic packaging units, on which a continuous tube is formed from the packaging material supplied in strip form; the strip of packaging material is sterilized on the packaging unit itself, e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution, which, after sterilization, is removed, e.g. vaporized by heating, from the surfaces of the packaging material; and the strip of packaging material so sterilized is maintained in a closed sterile environment, and is folded and sealed longitudinally to form a tube.
The tube is filled with the sterilized or sterile-processed food product, and is sealed and cut at equally spaced cross sections to form pillow packs, which are then folded mechanically to form the finished, e.g. substantially parallelepiped-shaped, packages.
Alternatively, the packaging material may be cut into blanks, which are formed into packages on forming spindles, and the resulting packages are filled with the food product and sealed. One example of such a package is the xe2x80x9cgable-topxe2x80x9d package commonly known as Tetra Rex (registered trademark).
Opening devices for packages of the above type are known which substantially comprise a frame defining a pour opening and fitted over a hole in one wall of the package; a partition member connected to the frame to close the pour opening, and which is detached from the frame along a preferential tear line; and a pull-off tab having one end connected to the partition member, and which is pulled by the free opposite end to detach the partition member from the frame along the preferential tear line and so expose the pour opening.
When the preferential tear line is a closed line, so that the partition member is detached completely from the frame, such opening devices also comprise a threaded cap, which is fitted to the frame to close the pour opening once the partition member is removed.
Though efficient, opening devices of the above type still leave room for further improvement.
One problem posed by this sort of opening device is that, when removing the partition member, the pressure applied on the lateral walls of the package by the user""s hand holding the package may result in some of the product squirting out.
Moreover, opening devices of the type described normally feature tamperproof members, such as plastic rings connected coaxially to the caps by radial, break-off connecting points, the condition of which is not always easily discernible by the consumer at the time of purchase, with the obvious consequences this entails.
It is an object of the present invention to provide an opening device for packages of pourable food products, designed to eliminate the aforementioned drawbacks typically associated with known opening devices.
According to the present invention, there is provided an opening device for a package containing a pourable food product, said device comprising a peripheral member defining a pour opening; a partition member connected to said peripheral member to close said pour opening, and which is at least partly detachable from the peripheral member along at least a first preferential tear line; and an opening member connected to said partition member and which is operated to detach the partition member from said peripheral member along said first preferential tear line and so expose said pour opening; characterized by comprising an air inlet hole formed in said partition member; and a bridge member connecting said opening member to said partition member and having sealing means for sealing said hole and which are broken by operation of said opening member to allow air through the hole prior to commencing detachment of said partition member from said peripheral member.